textproduct: Albany

WHAT HAS CHANGED

Convective Outlook adjusted slightly for Thursday, with Slight Risk now limited to far southern parts of the areas (Ulster, Dutchess and Litchfield Counties).

Have expanded Heat Advisory into southeastern Vermont for Friday, with heat index values expected to be in the mid 90s there in the afternoon/early evening on Friday.

KEY MESSAGES

1) Above normal temperatures and high humidity levels will continue through Friday. Heat index values will be high enough to allow for an increased risk in heat related illnesses in valley areas on Thursday and much of the region on Friday.

2) There is a chance for thunderstorms each day through Friday, especially in the afternoon and evening hours. Some storms could be severe with damaging winds and hail, especially on Thursday and Friday. Storms may be capable of producing heavy downpours as well.

3) Additional showers and thunderstorms are possible on Sunday associated with another cold front.

DISCUSSION

KEY MESSAGE 1...

Our region is under rising heights aloft ahead of a slow moving upper level trough over the central CONUS and Great Lakes. At the surface, high pressure is located just southeast of the area off the eastern seaboard, with a moist southerly flow in place over the area.

850 hpa temps continue to be very warm, with expected values in the +16 to +20 C range. These values are about 1-2 STD above normal based off the latest NAEFS. These values look to peak on Friday ahead of an approaching frontal system.

As a result, high temperatures look to be well into the 80s across most valley areas on Thursday. Some parts of the mid Hudson Valley may reach the lower 90s. On Friday, most areas valley areas will reach the lower 90s with some mid 90s possible in the mid Hudson Valley. Dewpoints have been rising over the past few days with current values already into the 60s. Dewpoints will remain in the upper 60s to low 70s through Friday.

Heat index values will be in the upper 80s to mid 90s on Thursday and widespread 90s to around 100 degrees on Friday for valley areas. Even high terrain areas will see unusually high heat index values on Friday as well. Heat Advisories are in effect for the Capital Region and mid Hudson Valley on Thursday, with much of the region for Friday, outside of the highest terrain of the Adirondacks, central Catskills, southern Greens, northern Taconics and northern Berkshires. Heat Risk values are widespread in the moderate category (level 2 of 4), with some localized areas in the major category (level 3 of 4). People should take precautions to avoid heat-related illnesses for Thursday and Friday by taking breaks in the shade, drinking water and spending time in air conditioning. There should be slightly cooler and less humid conditions arriving this weekend behind a cold front, which should ease the concern for heat related illnesses.

KEY MESSAGE 2...

There will be the potential for convection over the next few days. For this afternoon into this evening, there is a broken line of showers and embedded thunderstorms over the Finger Lakes and central NY and this will head towards the area for later today. 0-6 km bulk shear values are very low today due to main height falls and best forcing still well off to the west and mid level lapse rates are poor due to the warm temps aloft. As a result, widespread strong storms are not expected today. An isolated storm could be capable of producing damaging winds as it collapses, but this looks fairly limited and most storms won't be severe today. SPC has a marginal risk scrapping into western areas, but the main threat looks off to the west. Storms will diminish after sunset due to the loss of daytime heating.

Instability looks a little better on Thursday compared to today due to more heating and less cloud cover and continued high dewpoints. Still, the best forcing is still fairly far to the west. Coverage off storms actually looks a little less than today, but storms could have some damaging wind gusts due to high DCAPE and strong low level lapse rates. Based off the CAMs, the best storms may be mainly south of the area, but southern areas could be impacted by this. SPC has a slight risk for southern parts of the CWA into the mid Atlantic States so this makes sense.

On Friday, the surface cold front will be approaching, as the main upper level trough starts to shift eastward. Friday looks to be the best chance for strong storms, with a widespread Slight Risk over the area and there should be the highest coverage of showers and storms ahead of the front on Friday evening. A broken line of storms may move west to east across the area and 0-6 km bulk shear may be around 30 kts.

For all three days, any storm will also be capable of producing heavy downpours, as high PWATs and slower storm motion may lead to flooding of urban and low lying areas. Antecedent conditions have been fairly dry, but high rainfall rates may lead to some localized issues if rainfall occurs in a vulnerable location.

KEY MESSAGE 3...

Another cold front looks to cross the region later on Sunday. More showers and thunderstorms are expected just along or ahead of the front. With temps in the 80s, there could be enough instability for some more stronger storms, although the frontal timing is still in question. For now, will go with chc to likely POPs and continue to monitor model trends for this day.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

Through 18Z Thursday... VFR conditions initially prevail across all terminals, which will give way to scattered afternoon and evening showers/thunderstorms, particularly at KGFL, KALB, and KPOU. There is still low confidence regarding exact timing, strength, and extent of these systems, which is highlighted by PROB30 groups at the aforementioned terminals. However, thunderstorms could bring cigs down to MVFR and increase winds temporarily. Some lingering showers are possible after sunset tonight at all terminals which could also bring cigs down to MVFR. After the showers move out of the region, low-level moisture could stick around and create widespread misty/foggy conditions, reflected by TEMPO groups in the early morning hours of Thursday. This could bring cigs down to IFR and vis down to MVFR/IFR if this does develop. VFR cigs and vis are expected to fully return after 11Z-12Z, with some low level clouds expected to linger through the end of the TAF period.

Southerly winds start off this TAF period, with gusts up to 15-20 kts expected at KALB, KPOU, and KPSF. However as mentioned before, isolated thunderstorms could bring stronger winds/gusts. Winds are expected to weaken overnight between 00Z-04Z while beginning to shift more southwesterly. After 11Z Thursday, winds will continue to shift and prevail out of the west around 5-7 kts through the end of the TAF period.

Outlook...

Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Friday: High Operational Impact. Likely SHRA...TSRA. Friday Night: Moderate Operational Impact. Likely SHRA...TSRA. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: Moderate Operational Impact. Breezy. Chance of SHRA...TSRA. Sunday Night: High Operational Impact. Likely SHRA. Monday: Low Operational Impact. Slight Chance of SHRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...Heat Advisory from noon to 8 PM EDT Thursday for CTZ001-013. Heat Advisory from noon to 8 PM EDT Friday for CTZ001-013. NY...Heat Advisory from noon to 8 PM EDT Thursday for NYZ049-052- 053-059-060-064>066. Heat Advisory from noon to 8 PM EDT Friday for NYZ038>041-043- 047>053-059>061-063>066-082>084. MA...Heat Advisory from noon to 8 PM EDT Friday for MAZ025. VT...Heat Advisory from noon to 8 PM EDT Friday for VTZ015.